In situ small-angle X-ray scattering measurement at the Very Small Angle Neutron Scattering Instrument at the China Spallation Neutron Source.

Abstract

Small-angle X-ray and neutron scattering (SAXS and SANS) offer complementary insights into multi-scale and multiphase structures. Efforts have been made to integrate SAXS into SANS instruments, with only D22 at the Institut Laue-Langevin successfully implementing a SAXS setup; this was constrained to a horizontal geometry due to space limitations and high radiation noise. Here, we introduce an in situ vertical SAXS setup at beamline 14, Very Small Angle Neutron Scattering (VSANS) instrument, at the China Spallation Neutron Source. The compact vertical SAXS instrument without a beam stop, measuring 87 cm × 93 cm × 240 cm (W × L × H) and featuring a hoisting frame, can be easily installed in the VSANS sample room within 5 h. Utilizing a 50 mm-diameter neutron collimation guide, we can simultaneously detect X-rays from below and neutrons from behind, with the backboard of the SAXS chamber coated in a boron-aluminium alloy to reduce neutron background interference. Through testing with standard samples like deuterated and hydrogenated PEG, silver behenate, LaB₆, and glass carbon, we demonstrate that concurrent neutron and X-ray measurements are successful.